Pygmy Horses in My Living Room
by John Manrow
First published in The Fish Flash, Greater Portland Aquarium Society, May 1998
Aquarticles
There has been quite an increase in the number of requests for information on seahorses
lately, particularly the pygmy or dwarf seahorse, Hippocampus zosterae. This may
be due to the May 1998 issue of TFH magazine, which contained three related articles. This
article is about some of my experiences over the years keeping this unusual fish.
It was because of my desire to keep living seahorses that I set up my first saltwater
aquarium in 1969. I used a plastic 10 gallon tank with a Metaframe Hi-Fi undergravel
filter and silica sand as a substrate. After setting up the tank, I added two bags of Rila
saltwater mix, enough for 10 gallons of artificial seawater mix. I allowed the tank to run
at the specific gravity of 1.025 for a week before purchasing a pair of large Atlantic
seahorses, Hippocampus erectus, for $3.95 apiece. This seemed a high price for me
to pay, since neon tetras sold eight for a dollar at the time.
The seahorses took immediately to their new home, swimming about, snapping up live
brine shrimp, which I was already buying for my freshwater fish every Tuesday for $.35 a
portion (those portions seemed a lot larger than what we are getting now, and actually
seemed to last a week!). At the time I was still living with my parents just a few miles
from the salt ponds where the brine shrimp were harvested.
All was going well with seahorse keeping until suddenly no live shrimp were available.
I was told it was because of heavy rains, so I tried frozen brine. The seahorses were very
hungry by this time. They would follow a dead brine shrimp, and when it was realized it
wasn’t moving, interest was lost in the shrimp. Then another shrimp would be followed
with the same result. When live brine was available a few weeks later, it was too late.
The two seahorses starved, rather than eat non-living food. I had read the booklet
"Keeping Seahorses" by Robert & P.L. Straughan over and over, but was not
prepared for running out of live food. Now I had two dried seahorses and moved on to
keeping other tropical marine fish and invertebrates. I decided that if I couldn’t
provide proper food for a fish, I wouldn’t attempt to keep it. I did occasionally
order seahorses for customers when I entered the pet trade in 1974, but it wasn’t
until I set up my first mini-reef in 1986 that I found the seahorse to thrive. In the
presence of live rock and full spectrum lighting, there was an abundance of marine life -
copepods, rotifers, and amphipods - to supplement the diet.
About ten years ago I ordered six pair of H. zoster (dwarf seahorses) from
Aqualand Pets in Florida. They arrived in the mail a few days later. I had a 15 gallon
tank with two 40 watt full spectrum fluorescent lights. I use Penn Plax undergravel
filters with modifications. One of the adjustable lift tubes remains in the corner
modified into a co-current protein skimmer, while the other u/g plate is positioned so the
lift tube is situated at the back center of the tank. The lift tube extends above the
water surface. The Marineland P110 Penguin filter with Bio-Wheel was used with the intake
tube inserted in the u/g lift tube. This allows water to be drawn from the aquarium
without filtering out the brine shrimp nauplii fed to the dwarf seahorses. The substrate
consisted of a crushed coral-live sand mixture. There were four or five Florida plant
rocks with heavy growth of Caulerpa spp, Halimeda, Acetabularia, and
other macro-algae.
About three days after receiving the shipment of fish, a male delivered about thirty
seahorse larvae, complete with prehensile tails! I had two hatching jars for brine shrimp
which I started on alternate days, so I have newly hatched nauplii every morning. I
decapsulate the brine shrimp cyst before hatching for increased hatch and ease of
harvesting. I found the gestation of dwarf seahorses to be ten days. After delivery the
male will sometimes be seeking out a gravid female to deposit more eggs in his breeding
pouch. Prior to spawning the pair will quiver rapidly. The male inflates his brood with
water. The pair then release from their holdfasts and meet in the water column. Their
tails intertwine, the female inserts her ovipositor and transfers the eggs into the
male’s pouch, where they are fertilized internally. As I mentioned before I had six
pair to start with and ended up with hundreds. I seems that if dwarf seahorses have a
continuous (and I mean continuous!) supply of food, there is no stopping them from
reproducing.
After the larvae were delivered, they were transferred by the means of a 5/16"
diameter, 12" long rigid plastic dip tube to a 10 gallon rearing tank, also heavily
planted. Providing food for the young would be much easier with rotifers until about 3 or
4 weeks old, then feeding brine shrimp nauplii.
At the time I was not involved with GPAS, and could not find many people willing to
hatch brine shrimp eggs to properly feed them. When a store was
found willing to take them, I traded my remaining stock, along with a pair of Hippocampus
ingens and some shrimpfish for test kits and books.
For the year or so that I kept these little guys it was quite an adventure, but
providing a constant supply of newly hatched brine shirmp was preventing a trip out of
town for more than twelve hours - impossible for me at the time.
If you are interested in giving dwarf seahorses a try, I feel it will be a very
exciting and rewarding experience. My advice is to acquire only one or two pairs, have a
rotifer culture going, and some plants and rocks in the aquarium.
An excellent source for purchasing dwarf seahorses is Aqualand Pet Center, PO Box
55-7365, Miami FL 33255-7365.
Information on the Internet:
Seahorse Research Society: http://members.aol.com/gatesma/private/Seahorse/index
Project Seahorse: http://www.ayware.co.uk/seahorses/index.htm
Aquatic Bookshop: http://www.seahorses.com
Breeders Registry: http://www.breeders-registry.gen.ca.us/database/HIPZOS02.htm
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